The “iceberg of disease”

National mortality and hospital utilisation statistics present an incomplete picture of the burden of lung disease. Variations in disease coding and death certification may lead to spurious international differences, and for many diseases, hospital admissions and deaths are only the “tip of the iceberg”.

Sources of routinely collected data do not extend beyond deaths and hospital admissions for all respiratory conditions, but for some diseases it is possible to place the routine data into context against the frequency of the condition in the general population. Figure 7 summarises the burden of asthma, COPD, lung cancer and tuberculosis in EU28 countries, taking data from a range of sources for recent years.

These estimates highlight the widespread nature of obstructive lung disorders (asthma and COPD), for which a substantial proportion of patients are managed in the community and never reach hospital. In contrast, most new (incident) cases of lung cancer and tuberculosis come to the attention of hospital services. For tuberculosis, deaths represent only the tip of the iceberg, but for lung cancer, which is often rapidly fatal once diagnosed, the incidence and death rates are similar.